1. Field
The present disclosed embodiments relate generally to communications and more specifically to adaptively managing packet jitter in a packet-switched wireless communications system.
2. Background
In packet switched networks, the sending computer breaks a message into a series of small packets, and labels each packet with an address telling the network where to send it. Each packet is then routed to its destination via the most expedient route available, which means that not all packets traveling between the same two communications systems will necessarily follow the same route, even when they are from a single message. When the receiving computer gets the packets, it reassembles them into the original message.
Because each packet is handled separately, it is subject to a particular amount of delay that will be different from the delay times experienced by other packets within the same message. This variation in delay, known as “jitter,” creates additional complications for receiver-side applications that must account for packet delay time when reconstructing messages from the received packages. If the jitter is not corrected, the received message will suffer distortion when the packets are re-assembled.
Unfortunately, in VoIP systems that operate over the Internet, there is no information available that a de-jitter buffer can use to foresee changes in packet delay, and thus the de-jitter buffer is unable to adapt in anticipation of such changes. Typically, the de-jitter buffer must instead wait for the arrival of packets in order to detect changes in packet delay by analyzing packet arrival statistics. Thus, de-jitter buffers tend to be reactive, adjusting if at all only after packet delay changes have occurred. Many de-jitter buffers are incapable of changing at all, and are simply configured to have conservatively large sizes, which, as explained above, may add unnecessary delay to message playback and cause a user's experience to be sub-optimal. There is therefore a need in the art for adaptive delay management for efficiently removing jitter from packet transmissions in a communication system that has variant channels.